Mobility is an important aspect of telecommunications services. Mobility management refers to the process of tracking and maintaining location information and status regarding a mobile communication device. For example, one of the reasons for the popularity of wireless telephones is that people who are highly mobile can still receive and place telephone calls from a single wireless telephone. Mobility management allows wireless telephones to move about within a service area while still being able to place and receive calls.
In addition to wireless telephones, mobile computing devices, such as laptop computers, palmtop computers, and personal digital assistants (PDAs), are becoming popular. Such devices are particularly useful for people who are highly mobile. These devices allow such individuals to connect to office networks while traveling. Mobility management with respect to mobile computing devices allows users of these devices to connect to data networks and to send and receive data while connected to the data networks from a location which is away from the devices home location.
One popular protocol for the exchange of information over data networks is Internet Protocol (IP). However, mobility management for such mobile computing devices presents a problem because IP was originally developed with the assumption that devices would be connected to the network at fixed locations. As such, a device would be assigned a unique IP address, which would define the device's physical connection to the network. Since a mobile computing device is not permanently connected to the network at any single point, an IP address associated with the mobile computing device does not define the device's physical connection to the network, thus violating an important assumption of IP addresses. Various techniques have been developed for mobility management as it relates to these mobile computing devices. One such technique is described in U.S. Pat. No. 5,159,592 which uses a nameserver and pseudo-IP addresses to associate fixed names of mobile units with the pseudo-IP addresses. Even though the pseudo-IP address may change, the current pseudo-IP address of a mobile unit can be determined by looking up the fixed name in the nameserver. A technique called tunneling is described in U.S. Pat. No. 5,325,362 which uses special routers to store current locations of mobile units in tables. When a router receives a packet for a mobile unit, the packet is forwarded, or tunneled, to the appropriate current location. U.S. Pat. No. 5,708,655 describes the assignment of temporary IP addresses to mobile units such that the mobile unit can provide the temporary IP address to another computer to effectuate the transfer of data between that computer and the mobile unit. These techniques provide some level of mobility management for mobile computing devices.
However, the above described techniques for mobility management for mobile computing devices focus on the data communication functions of these devices. However, it is noted that mobile computing devices can be configured with appropriate hardware and software so that these devices can engage in voice communication via a data network using IP. However, the techniques described above do not apply mobility management techniques to mobile computing devices being used for IP voice communication over data networks.
What is needed is an integrated mobility management solution for providing voice calling services to mobile computing devices connected to a data network.